1. Field of the Invention
The present invention relates to an electromagnetic actuator for operating at least one movable contact of a switch into a switched-on position or a switched-off position, wherein the electromagnetic actuator has a first magnetic circuit with a switching-on coil for making a movable and a fixed pole body move towards one another until the switched-on position is reached, a second magnetic circuit, separate from the first magnetic circuit, with a permanent magnet and a retaining plate joined to the movable pole body, for holding the actuator in the switched-on position against any spring or other forces when the switching-on coil is not energised, and a switching-off coil that operates to counteract the magnetic field in the second magnetic circuit so that the actuator can return to a switched-off position. The second magnetic circuit contains the permanent magnet, the retaining plate, the switching-off coil and a circuit body closing the second magnetic circuit, wherein the second magnetic circuit provides an increasing force of attraction between the circuit body and the retaining plate during the movement from the switched-off position into the switched-on position.
In further aspects this invention relates to a method for the production of an electromagnetic actuator and to an assembly for fixing an actuator, such as an actuator according to the present invention, in a switching installation which has at least one movable contact of a switch.
2. Background Information
An electromagnetic actuator of this type is disclosed in International Patent Publication WO 99/14769. As a result of the separate magnetic circuits, the actuator can be optimised as far as the switching-on and switching-off speeds and the requisite switching-on and switching-off energy are concerned. However, the actuator described in this publication can be even further improved, both in terms of operational use of the actuator and in terms of production of the actuator.